Russia has dismissed allegations that its military struck U.S.-backed forces in war-torn Syria, injuring several allied fighters.

Defense Ministry spokesman Major General Igor Konashenkov said on September 17 that Russian strikes only hit targets in areas under the control of the extremist group Islamic State (IS).

Konashenkov that the Russian military informed the United States well in advance of its operational plans.

"To avoid unnecessary escalation, the commanders of Russian forces in Syria used an existing communications channel to inform our American partners in good time about the borders of our military operation in Deir al-Zor," he said.

The comments come after the U.S.-led coalition battling IS militants in Syria said the Russian military on September 16 struck forces of a U.S.-backed Kurdish-Arab militia in Syria.

"Russian munitions impacted a location known to the Russians to contain Syrian Democratic Forces and coalition advisors," a statement said. "Several SDF fighters were wounded and received medical care as a result of the strike."

It added that coalition advisers who were present "were not wounded as a result of the Russian strike."

Earlier, the SDF accused Russian jets of bombing its forces in Deir al-Zor Province, injuring six of its fighters in the last major IS stronghold in Syria.

The United States and Russia back separate military offensives in the Syrian war, both of which are advancing against IS forces in the east of the country near Iraq.

Russia and Iran back Syrian President Bashar al-Assad in the country's six-year-old war, while the United States and Turkey support various rebel groups opposed to the Damascus government.

IS fighters, who captured large swathes of Syrian territory in 2014, are opposed by all sides and are being driven from most of their strongholds by the separate government and rebel campaigns.

Washington and Moscow have largely stayed out of each other's way in their fight against IS in Syria, with the Euphrates River frequently serving as a dividing line.

The commander of the U.S.-led coalition, Lieutenant General Paul Funk, said in the September 16 statement that coalition officials "are available and the de-conflictation line with Russia is open 24 hours a day."

"We put our full efforts into preventing unnecessary escalation among forces that share ISIS as our common enemy," Funk said, using an alternate acronym for the extremist group.

The statement added, "Coalition forces and partners always retain the right of self-defense."